In the context of improved survival from HIV infection itself, chronic obstructive pulmonary disease (COPD); a form of lung disease that includes emphysema, which makes breathing difficult) is emerging as an important cause of morbidity and perhaps ultimately mortality in this population. HIV-infected patients are at increased risk of chronic obstructive pulmonary disease, likely due to multiple factors, including an increased presence of smoking, chronic inflammation and progression of immunodeficiency, oxidant stress (excessive levels of natural chemicals called oxidants and free radicals that can damage tissue), and respiratory infections. While natural history data on COPD are limited in the era of potent antiretroviral therapy, earlier data suggest that the course of emphysema may be accelerated in this population. Our preliminary data suggest that several matrix metalloproteinases (MMPs) derived from alveolar macrophages (a type of immune cell found in the lungs) have an increased cellular response in HIV-infected smokers, which could contribute to accelerated emphysema. Matrix metalloproteinases are enzymes that break down the structural support of tissues, including the airways in the lung.